Color kinescopes and methods of making same



Oct. 23, 1956 V w, EPSTEIN 2,767,457

COLOR KINESCOPES AND METHODS OF MAKING SAME Filed Nov. 1, 1954 i :5Sheets-Sheet 1 0 INVENTOR. 5 0 9100 Wffisri/zv Oct. 23, 1956 D. w.EPSTEIN 2,767,457

COLOR KINESCOPEZS AND METHODS OF MAKING SAME Filed NOV. 1, 1954 3Sheets-Sheet 2 INVENTOR. Q4 W0 W 5 5mm 4 oils/5V 1956 D. w. EPSTEINKINESCOPES AND METHODS OF MAKING SAME Filed NOV. 1, 1954 -3 Sheets-Sheet3 INVENTOR. pfi'V/D W6 5 TE/N 2,767,457 Patented Get. 23, 1956 COLORKINESCOPES AND METHODS OF MAKING SAME David W. Epstein, Princeton, N.J., assignor to Radio Corporation of America, a corporation of DelawareApplication November 1, 1954, Serial N 0. 466,016 15 Claims. (Cl.29-25.13)

This invention relates to improvements in the art of manufacturing colorkinescopes and other cathode ray tubes of the type having aplane-of-defiection and containing a screen unit comprising a maskcontaining a multiplicity of systematically arranged apertures throughwhich beam electrons pass along different angularly related paths intheir transit from the plane-of-deflection to selected ones ofmetallized dot-like or line-like elemental phosphor areas on the targetsurface of a nearby screen.

One of the problems encountered in manufacturing a screen for use incolor kinescopes of the type briefly described above, and for analogoustubes, has been the problem of depositing the phosphor particles in thedotlike or line-like elemental areas. One method of applying thephosphor particles which has been used heretofore is the directphotographic method wherein the different color emitting phosphors arelaid down, one at a time, on the screen-plate. In this method a coloremitting phosphor, as well as a photosensitive emulsion, is introducedinto the tube and is exposed to a point source of light through the maskwhich exposes the emulsion in a particular pattern. When this step hasbeen completed the mask is removed and after development of the exposedareas of emulsion, the emulsion and phosphor adhere to the screen-plate,while the emulsion which was not exposed as well as the correspondingphosphor particles are removed. The process is then repeated for theremaining two colors. In the direct photographic methd the screen unitmust be disassembled several times, for the purpose of sensitizing theseparately photographed red, blue, and green phosphor patterns of thescreen, and subsequently reassembled prior to aligning the unit with abattery of electron guns in the tube in which the screen is to beutilized.

Accordingly, a principal object of this invention is to provide animproved cathode ray tube wherein access may be had to a foundationsurface for a color screen through the envelope wall.

Another object of this invention is to provide an improved method ofdepositing phosphor particles wherein the particles are inserted throughthe walls of the envelope.

A further object of this invention is to provide a new method of andmeans for applying an electron permeable metal coating of substantiallyuniform thickness through an apertured mesh to a permanently mountedscreen.

A still further object of this invention is to provide a. new method ofsettling color emitting phosphor particles through a mask and onto asupport plate wherein excess phosphor particles may be removed from boththe mask and the support plate.

Stated generally, the foregoing and other objects are there is providedmeans for inserting the phosphor particles and, or the photosensitiveemulsion, through the wall of an envelope having permanently sealedtherein an apertured mask. The materials are inserted into a spacebetween the mask and the screen support plate.

A method of manufacturing is provided such that, when the directphotographic method of applying phosphor particles is employed, there issufficient room to utilize a' high energy light source. When an electronsensitive mosaic pattern is to be provided With an electron transparentmetallic layer, means are provided to produce a uniform layer of themetallic material, from a large source, through the apertured mask.

The invention is described in greater detail in connection with theaccompanying three sheets of drawings, wherein:

Fig. 1 is a fragmentary sectional view of an envelope for a kinescope,having sealed therein an apertured mask, in the process of having ascreen unit applied therein in accordance with the principles of thisinvention;

Figures 2 through 4 are fragmentary sectional views of further steps inthe manufacture of the tube shown in Fig. l in accordance with thisinvention;

Fig. 5 is a longitudinal sectional view of a completed tube inaccordance with this invention; and,

Fig. 6 is a fragmentary sectional view of an embodiment of a kinescopetube in accordance with this invention.

Referring now to the drawings in detail, Fig. 1 shows a partialsectional view of an envelope 11 for a tri-color kinescope havingpermanently sealed therein an apertured mask 16. The mask 16 issupported adjacent to,

a glass face plate, or screen, 14. In accordance with this invention themask 16 may be supported within the envelope 11 prior to the sealing offace plate 14 to the cone portion 13 of envelope 11; The glass faceplate 14 may be of any desired shape, e. g. circular or rectangular, andcurvature, e. g. fiat or spherical. In the instant case the glass faceplate 14 is in the form of a circular section of a spherical shell. Theface plate 14 is sealedto a lip 12 on the cone portion 13 of envelope11. Any of the conventional glass-to-metal seals may be utilized forsealing the face plate 14 to the lip 12.

The mask 16 may be of any type of conducting material, and preferablyincludes some type of temperature compen sation means such as hinges 17to insure that the predetermined relationship between the mask 16 andface plate 14 is maintained during the operation of the tube.

achieved in accordance with this invention by permanently When, as inthe instant case, the phosphor material is to be laid down directly onthe inner surface of the curved face plate 14, the mask 16 isappropriately curved. In accordance with this invention a temperaturecompensated mask 16 is permanently bonded to the inner walls of cone 13.This bond may be made by a weld between a flat portion 19 of mask 16 andthe inner surface of the metallic cone 13. It is also within thecontemplation of this invention to permanently bond the mask 16 to theinner walls of cone 13 by other well-known means, such as support pinsor ridges (not shown). The mask may be made of a copper-nickel alloy ofapproximately copper and the balance nickel.

Generally, it will be found to be advantageous to bond the mask 16 tothe inner periphery of cone portion 13. prior to the sealing of theglass face plate 14 to the lip 12. In accordance with this invention,color emitting phosphor particles are deposited in any of theconventional patterns, i. e. dot-like or line-like patterns, after themask 16 has been permanently sealed into the cone portion 13 of envelope11. When the mask 16 has I well-known in the art. The aluminum coatingis a continuous and is an even coating due to the large size of theevaporator 53, irrespective of the shadowing eifect of the mask 16.

After the conductive coating 55 has been applied to the filming lacquer40, the layer of filming lacquer is baked out of the envelope and theconductive coating 55 provides a smooth surface over the color emittingphosphor particles v34, 35, and 36. The backing out of filming lacquer40 also removes any of the filming lacquer material that may have beendeposited on mask 16. When this step has been completed the cone 13 maybe sealed to a funnel 58 having sealed therein a battery of electronguns 59, 60, and 61. The funnel 58 may be aligned with the cone 13 bywell-known means such as alignment pins 31 (shown in Fig. 2), on thebelieved portion of cone 13. The funnel 58 may be sealed to the metalliccone 13 by any of the well-known glass-to-metal seals.

As seen from Fig. 5 the completed tube has a planeof-deflection for thethree electron beams 62, provided by deflection yoke 57, each of whichcorresponds to the exact location of the point light source 30 in one ofits locations shown in Fig. 2. Thus, the electron beams 62 from guns 59,60, and 61 each strike one of the arrays of color emitting phosphors 34,3'5, and 36 which are arranged in the conventional hexagonal pattern ofred, blue, and green. =Each triad group of phosphors is arranged behindan aperture 20 in the mask 16. When the tube 10 has been completed thetubulation 28 may be utilized for exhausting the envelope 11 and may bepinched olf by any of the well-known low temperature sealing methods forsuch an element.

Referring now to Fig. 6 there is shown a partial sectional view of anembodiment of this invention comprising a glass envelope 63 for use as atri-color television tube. As in the embodiment described in Figures 1through 5 there is provided between a permanently 'secured mask 16' anda face plate 14 a tubulation 65 which may be utilized for inserting thecolor emitting phosphor particles and emulsion as previously described.The mask 16' is bonded to support pins 67 which are bonded within thecap portion 69 of envelope 63. When the mask is affixed into cap 69, thecap is sealed by means of seal 71 to a cone 70. As in the metal tube themask 16' is temperature compensating and the entire process ofmanufacturing the tube occurs after the mask 16' has been sealed intothe cap portion 69 and the cap sealed to the cone portion of theenvelope 63. The process for completing the tube is substantially thesame as that previously described.

As should be obvious to those skilled'in the art this invention providesa method of and means for manufacturing a color television tube afterthe mask and face plate are sealed to the cone portion of an envelope.The features of this invention permit tube manufacturers to obtain thecombination of a cone, face plate, and mask from an envelope vendor,either glass or metal, and complete the tube by economical methods.

What is claimed isz 1. Method of depositing color emitting phosphors ona screen plate of a cathode ray tube of the type including an aperturedmask spaced from said screen plate, said method including the step ofapplying said phosphors onto said screen plate through a wall of theenvelope of said tube at a point intermediate said screen plate and saidapertured mask.

2. Method of making a cathode-ray tube of the kind having an envelopecontaining a plane-of-defiection and a target-assembly comprising a maskspaced from a foundation surface of a phosphor screen, said maskcontaining a multiplicity of apertures systematically arranged in apattern to define a target area through which an electron-beam normallypasses from one of three substantially fixed points in saidplane-of-deflection to preselected ones of the elemental areas of asimilar pattern on said foundation surface of said screen, said envelopein:

ing an open neck-portion through which access may be had to said pointsin said plane-of-deflection, said method comprising; permanentlysecuring said mask and said foundation surface in spaced relationshipwithin the main chamber of said envelope, inserting a color emittingphosphor into said envelope, evenly distributing said phosp hor on saidfoundation surface, inserting a photosensitive emulsion through anopening in the wall of said envelope and into said space between saidmask and said foundation plate, evenly distributing said emulsion onsaid phosphor, removably locating a projector in said open neck portionof said envelope in a position whereat the outlet of said projectorcoincides with one of said fixed points in said plane-of-deflection,projecting along a multiplicity of angul'arly related straight paths,from said outlet, emanations capable of passing through saidmaskapertures and of recording upon said target surface the pate-r11 ofsaid apertures whereby said emulsion is de-- veloped in said pattern,removing said projector from said neck, removing the undevelopedportions of said emulsion and the corresponding phosphor particlesthrough said opening, repeating said steps utilizing a second and athird color emitting phosphor and a second and a third of saidsubstantially fixed points, Wetting the array of color emitting phosphorparticles, spraying a filming lacquer onto said phosphor particlesthrough the apertures in said mask, evaporating an electron perviousconductive film onto said lacquer and through the apertures in saidmask, baking said envelope to remove said lacquer, and mounting threesources of beam-electrons in said neck in a position whereat the beamfrom each of said sources is in line with one of said fixed points insaid plane-of, deflection.

3. The method of claim 2 as applied to the manufacture of a tri-colorkinescope, and wherein the step of projecting emanations through saidmask from said projector is repeated with the outlet of the projectorlocated, successively, at each of the three points in theplane-ofdeflection each of which is peculiar to one of the three coloremitting phosphors of said tri-color kinescope.

4. A sub-assembly for use in the manufacture of a cathode-ray tube ofthe color kinescope variety, said sub assembly comprising a cone.portion of an envelope, a

transparent screenplate forming a closed end on said cone portion andadapted to support electron sensitive material on the inner surfacethereof, an apertured electrode permanently secured in said envelope andspaced from said screen-plate, and means through the wall of saidenvelope and opening into said space between said apertured elec: trodeand said screen plate for inserting said electron Sen sitive materialonto said screen plate.

5. A sub-assembly as in claim 4 wherein said cone is metallic and saidmeans includes a hollow metallic tubulation of the type capable of beingpinched off to form a low temperature seal.

6. A sub-assembly as in claim 4 wherein said cone is glass and saidmeans includes a hollow tubulation adapted to be sealed after saidelectron sensitive material is in; serted.

7. Method of making a cathode=ray tube comprising an envelope containinga target-assembly comprising an electrode containing a multiplicity ofapertures system= ati-cally arranged in a pattern to define a targetarea through which an electron-beam normally passes from one of threesubstantially fixed points in a planeof-deflection to pro-selected onesof the elemental areas of a similar pattern on a screen spaced from saidelectrode, said envelope having an open neck-portion through whichaccess may be had to said point in said plane-of-deflection, said methodcomprising; permanently seeming said apertured electrode and saidfoundation surface in spaced relationship within the main chamber ofsaid envelope, inserting a color emitting phosphor into said envelopethrough an opening into said space and through the wall of saidenvelope, evenly distributing said phosphor on said foundation surface,inserting a photosensitive emulsion into said envelope through saidopening, evenly dis: tributing saidemulsion on said phosphor, removablylocating a projector in said open neck portion of said envelope in aposition whereat the outlet of said projector coincides with one, ofsaid fixed points in said plane-ofdeflection, projecting along amultiplicity of angularly related straight paths, from said outlet,emanations capable of passing through said mask-apertures and ofrecording upon said target surface the pattern of said apertures wherebysaid emulsion is developed in said pattern, removing said projector fromsaid neck, removing the undeveloped portions of said emulsion and thecorresponding phosphor particles through said opening, repeating saidsteps utilizing a second and third of said substantially fixed points,wetting the resultant array of color emitting phosphor particles,spraying a filming lacquer onto said phosphor particles through theapertures in said mask, evaporating an electron pervious conductive filmonto said lacquer and through the apertures in said mask, baking saidenvelope to remove said lacquer, and mounting three sources ofbeam-electrons in said neck in a position whereat the beam from each ofsaid sources is in line with, one of said fixed points in saidplane-of-deflection.

8. Method of making a cathode-ray tube comprising an envelope containinga target-assembly comprising an apertured electrode spaced from afoundation surface of a phosphor screen, said apertured electrodecontaining a multiplicity of apertures systematically arranged in apattern to define a target area through which an electronbeam normallypasses to pro-selected elemental areas on said foundation surface; saidmethod comprising; permanently securing said apertured electrode andsaid foundation surface in spaced relationship within the top cap ofsaid envelope, securing a cone portion of said envelope to said top cap,inserting a color emitting phosphor into said envelope through anaperture in said top cap opening into said space between said aperturedelectrode and said foundation surface, evenly distributing saidphosphoron said foundation surface, inserting a photosensitive emulsioninto said envelope through said opening, evenly distributing saidemulsion on said phosphor, developing said emulsion in a pattern, andremoving the undeveloped portions of said emulsion and the excessphosphor particles through said opening.

9. Method of making a cathode-ray tube comprising an envelope containingan apertured electrode spaced from a foundation surface of a nearbyscreen; said method comprising; permanently securing said aperturedelectrode and said foundation surface in spaced-apart relationshipwithin the, main chamber of said envelope, inserting a color emittingphosphor into said envelope through an opening in the wall of saidenvelope and into said space between said apertured electrode and saidfoundation surface, inserting a photosensitive emulsion into saidenvelope through said opening, and projecting light from a sourcethrough the apertures in said apertured electrode for developing saidemulsion in a pattern.

10. Method of making a cathode-ray tube comprising anenvelope containinga mask electrode spaced from a foundation surface of a phosphor screen,said method comprising; permanently securing said mask and saidfoundation surface in spaced-apart relationship .within the main chamber of said envelope, inserting a color emitting phosphor into saidenvelope through an opening in said envelope and into said space betweensaid mask and said foundation surface, inserting a photosensitiveemulsion into saidenvelope through said opening, removably locating aprojector in an open neck portion of said envelope in a position whereatthe outlet of said projector coincides with a fixed point. intheplane-of-defiection of said tube, projecting along a multiplicity ofangularly related straight paths, from said outlet, light capable ofpassing through said mask-apertures and of recording upon said targetsurface the pattern ,of said apertures whereby said emulsion isdeveloped in said pattern, removing said pro- 'ector from said neck,removing the undeveloped portions of said emulsion and the correspondingphosphor particles, repeating said stepstutilizing a second and thirdcolor emitting phosphor and a second and a third substantiallyfixedpoint, wetting the array of color emitting phosphor particles,spraying a filming lacquer onto said phosphor particles through theapertures in said mask, evaporating an electron pervious conductive filmonto said lacquer and through the apertures in said mask, baking saidenvelope to remove said lacquer, and mounting electron beam producingmeans in said neck in a position whereat at least a portion of anelectron beam is in line with each of said fixed points in saidplane-of-defiection.

11. Method of making a cathode-ray tube comprising an envelopecontaining an apertured mask electrode spaced from a foundation surfacefor a phosphor screen, said method comprising; permanently securing saidmask andsaid foundation surface in spaced relationship within the mainchamber of a cathode-ray tube-envelope, settling a color emittingphosphor into said envelope through the apertures in said mask,introducing a photosensitive emulsion through-the wall of said envelopeinto the space between said mask and said surface, securing saidphosphor-onto said foundation surface in a pattern similar to thepattern of the apertures in said mask, removing the unsecured portionsof said phosphor particles from said surface and from said mask,repeating said steps utilizing a second and thirdcolor emittingphosphor, spraying a filming lacquer onto said phosphor particlesthrough the apertures in said mask, evaporating an electron pcrviousconductive film ontosaid lacquer and through the apertures in saidmask,baking said envelope to remove said lacquer, and mounting threesourcesof beam-electrons in said neck in a position whereat the beamfrom each of said sources is in line with one of said fixed points insaid plane-of-defiection.

l2. Amethod as in claim 11 wherein said unsecured phosphor particles arewashed from said mask and said foundation surface.

13. Amethod as in claim 11 wherein said unsecured phosphor particles areremoved through the wall of said envelope between said mask and saidfoundation surface.

14.. A sub-assembly for use in the manufacture of a cathode-ray tubecomprising an envelope including a transparent screen-plate having atarget surface area adapted to support an electron-sensitive target, amask mounted in permanently fixed spaced-relation with respect to saidscreen-plate, and said envelope having at least one aperture thereinopening into the space between said screen-plate and said mask.

15. The invention as set forth in claim 14 further comprisinga hollowtubular member sealed to said envelope and surrounding said aperture,and said tubular member being a material of the type adapted to bepinched ofif to form a low temperature seal.

No references cited.

